Molded parts used for photographic sensitive materials and resin compositions used to make thereof

Abstract

A novel resin composition for use in applications requiring low formaldehyde concentration levels. The novel composition comprising a stabilized polyacetal polymer with capped end groups is characterized by the concentration of formaldehyde generated from a formed object of the said composition in a closed environment being less than 20 ppm.

We claim: 
     
       1. A novel resin composition for use in applications requiring low formaldehyde concentration levels, comprising: a) about 97 to about 99.95 weight percent of a stabilized polyacetal polymer with capped end groups; and   b) about 0.05 to about 3 weight percent of an organic cyclic compound having an active imino group according to the formula: ##STR2## wherein R 1 , R 2 , and R 3  represent divalent organic radicals and said organic cyclic compound is selected from the group consisting of hydantoin derivatives and imidazole derivatives, and wherein a part molded from said resin produces an atmospheric formaldehyde concentration of less than about 20 ppm in an enclosed environment.     
     
     
       2. The resin composition of claim 1 wherein said stabilized polyacetal polymer is capped by the group consisting of --OCOCH 3 , --OCH 3 , and --OCH 2  CH 2  OH. 
     
     
       3. The resin composition of claim 1 wherein said organic cyclic compound is a hydantoin derivative selected from the group consisting of hydantoin, 5,5-dimethylhydantoin, 5,5-diphenylhydantoin, and allantoin. 
     
     
       4. The resin composition according to claims 1, 2, or 3 comprising about 0.05 to 3.0 weight percent of said organic cyclic compound. 
     
     
       5. The resin composition according to claims 1, 2, or 3 comprising about 0.06 to 2.0 weight percent of said organic cyclic compound. 
     
     
       6. The resin composition according to claims 1, 2, or 3 comprising about 0.067 to 1.0 weight percent of said organic cyclic compound. 
     
     
       7. The resin composition according to claims 1, 2, or 3 further comprising about 0.001 to 1.0 weight percent of a hindered phenol-type antioxidant. 
     
     
       8. The resin composition according to claims 1, 2, or 3 further comprising about 0.05 to 25 weight percent of a light-shielding material. 
     
     
       9. A molded part comprising the resin composition according to claims 1, 2, or 3. 
     
     
       10. The resin composition according to claim 8 further comprising about 0.5 to 5.0 weight percent of a thermal stabilizer selected from the group consisting of: a) a polyamide; b) a non-melting nitrogen-containing polymer compound; and c) a hydroxyl-containing polymer compound. 
     
     
       11. The resin composition according to claim 8 further comprising a filler selected from the group of: glass, fiber, carbon black or combinations thereof. 
     
     
       12. A method for reducing formaldehyde concentration in a closed environment from a molded part comprising a polyacetal resin composition, said method comprising: a) blending about 97 to about 99.95 weight percent of a stabilized polyacetal copolymer end-capped by --OCOCH3, --OCH3, or --OCH 2  CH 2  OH-- group with about 0.05 to about 3 weight percent of an organic cyclic compound having an active imino group according to the formula: ##STR3## wherein R 1 , R 2 , and R 3  represent divalent organic radicals and said organic cyclic compound is selected from the group consisting of hydantoin derivatives and imidazole derivatives, and   b) shaping said blend into a molded part by injection molding, blow molding, extrusion or coextrusion molding, compression molding, rotary molding, melt spinning, heat molding, or vacuum forming, wherein a part molded from said resin composition produces an atmoshpheric formaldehyde concentration of less than about 20 ppm in an enclosed environment.